Abstract
Development of therapies for neuropsychiatric conditions is one of the greatest challenges of modern medicine. Common limitations of traditional small molecule drugs include poor efficacy, off-target side effects and difficult druggability of many targets. In this study, we report a different approach deploying small engineered single domain antibodies, known as nanobodies, for the treatment of depression, a prevalent neuropsychiatric condition. We develop highly selective nanobodies for a recently discovered glycine receptor mGlyR crucially linked to pathophysiology of depression. Using a mouse model of stress-induced depression, we show that non-invasive intranasal delivery of nanobody produces rapid and lasting anti-depressant effect. We solve an atomic structure of mGlyR bound to nanobody and use a variety of cell-based approaches to reveal the mechanism of mGlyR modulation and its impact on neural circuitry. These findings support development of biologics for the treatment of intractable brain disorders.